package com.library.uiframework.widget.imageview;

import java.lang.ref.WeakReference;

import android.graphics.Bitmap;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;

/**
 * Created by brucelee on 3/1/16.
 */
class BlurTask extends AsyncTask<Object, Void, Bitmap> {
    private static final int CONST_16 = 16;
    private static final int CONST_8 = 8;

    private static final int MASK_HIGH = 0xFF0000;
    private static final int MASK_MID = 0x00FF00;
    private static final int MASK_LOW = 0x0000FF;

    private static final int ALPHA_CHANEL = 0xff000000;

    private Bitmap mBitmap;
    private WeakReference<NetworkImageView> mNetworkImageViewWeakReference;
    private int mBlurRadius;

    public void onDestory(){
        cancel(true);
    }

    public BlurTask(Bitmap bitmap, NetworkImageView networkImageView, int blurRadius) {
        mBitmap = bitmap;
        mNetworkImageViewWeakReference = new WeakReference<NetworkImageView>(networkImageView);
        mBlurRadius = blurRadius;
    }

    @Override
    protected Bitmap doInBackground(Object... params) {
        return fastBlurInJava(mBitmap, mBlurRadius);
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        super.onPostExecute(bitmap);

        NetworkImageView networkImageView = mNetworkImageViewWeakReference.get();
        if (networkImageView != null) {
            networkImageView.superSetImageDrawable(getDrawable(bitmap));
        }
    }

    protected Drawable getDrawable(Bitmap bitmap) {
        return new RoundedDrawable(bitmap);
    }

    public static Bitmap fastBlurInJava(Bitmap sentBitmap, int radius) {
        if (radius < 1 || sentBitmap == null) {
            return null;
        }
        int width = sentBitmap.getWidth(), height = sentBitmap.getHeight();
        if (width <= 0 || height <= 0) {
            return null;
        }
        return Bitmap.createBitmap(fastBlurToColorsInJava(sentBitmap, radius), 0, width, width, height, sentBitmap.getConfig());
    }

    private static int[] fastBlurToColorsInJava(Bitmap sentBitmap, int radius) {

        int w = sentBitmap.getWidth();
        int h = sentBitmap.getHeight();

        int[] pix = new int[w * h];
        sentBitmap.getPixels(pix, 0, w, 0, 0, w, h);

        int wm = w - 1;
        int hm = h - 1;
        int wh = w * h;
        int div = radius + radius + 1;

        int[] r = new int[wh];
        int[] g = new int[wh];
        int[] b = new int[wh];
        int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
        int[] vmin = new int[Math.max(w, h)];

        int divsum = (div + 1) >> 1;
        divsum *= divsum;
        final int dvFactor = 256;
        int[] dv = new int[dvFactor * divsum];
        int start = 0;
        for (i = 0; i < dvFactor; i++) {
            for (int offset = 0; offset < divsum; offset++) {
                dv[start + offset] = i;
            }
            start += divsum;
        }

        yw = 0;
        yi = 0;

        int[][] stack = new int[div][3];
        int stackpointer;
        int stackstart;
        int[] sir;
        int rbs;
        int r1 = radius + 1;
        int routsum, goutsum, boutsum, rinsum, ginsum, binsum;

        for (y = 0; y < h; y++) {
            rinsum = 0;
            ginsum = 0;
            binsum = 0;
            routsum = 0;
            goutsum = 0;
            boutsum = 0;
            rsum = 0;
            gsum = 0;
            bsum = 0;
            for (i = -radius; i <= radius; i++) {
                p = pix[yi + Math.min(wm, Math.max(i, 0))];
                sir = stack[i + radius];
                sir[0] = (p & MASK_HIGH) >> CONST_16;
                sir[1] = (p & MASK_MID) >> CONST_8;
                sir[2] = (p & MASK_LOW);
                rbs = r1 - Math.abs(i);
                rsum += sir[0] * rbs;
                gsum += sir[1] * rbs;
                bsum += sir[2] * rbs;
                if (i > 0) {
                    rinsum += sir[0];
                    ginsum += sir[1];
                    binsum += sir[2];
                } else {
                    routsum += sir[0];
                    goutsum += sir[1];
                    boutsum += sir[2];
                }
            }
            stackpointer = radius;

            for (x = 0; x < w; x++) {

                r[yi] = dv[rsum];
                g[yi] = dv[gsum];
                b[yi] = dv[bsum];
                rsum -= routsum;
                gsum -= goutsum;
                bsum -= boutsum;

                stackstart = stackpointer - radius + div;
                sir = stack[stackstart % div];

                routsum -= sir[0];
                goutsum -= sir[1];
                boutsum -= sir[2];

                if (y == 0) {
                    vmin[x] = Math.min(x + radius + 1, wm);
                }
                p = pix[yw + vmin[x]];

                sir[0] = (p & MASK_HIGH) >> CONST_16;
                sir[1] = (p & MASK_MID) >> CONST_8;
                sir[2] = (p & MASK_LOW);

                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
                rsum += rinsum;
                gsum += ginsum;
                bsum += binsum;

                stackpointer = (stackpointer + 1) % div;
                sir = stack[(stackpointer) % div];

                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
                rinsum -= sir[0];
                ginsum -= sir[1];
                binsum -= sir[2];
                yi++;
            }
            yw += w;
        }
        for (x = 0; x < w; x++) {
            rinsum = 0;
            ginsum = 0;
            binsum = 0;
            routsum = 0;
            goutsum = 0;
            boutsum = 0;
            rsum = 0;
            gsum = 0;
            bsum = 0;
            yp = -radius * w;
            for (i = -radius; i <= radius; i++) {
                yi = Math.max(0, yp) + x;

                sir = stack[i + radius];
                sir[0] = r[yi];
                sir[1] = g[yi];
                sir[2] = b[yi];
                rbs = r1 - Math.abs(i);
                rsum += r[yi] * rbs;
                gsum += g[yi] * rbs;
                bsum += b[yi] * rbs;

                if (i > 0) {
                    rinsum += sir[0];
                    ginsum += sir[1];
                    binsum += sir[2];
                } else {
                    routsum += sir[0];
                    goutsum += sir[1];
                    boutsum += sir[2];
                }

                if (i < hm) {
                    yp += w;
                }
            }
            yi = x;
            stackpointer = radius;
            for (y = 0; y < h; y++) {
                // Preserve alpha channel: ( 0xff000000 & pix[yi] )
                pix[yi] = (ALPHA_CHANEL & pix[yi]) | (dv[rsum] << CONST_16) | (dv[gsum] << CONST_8) | dv[bsum];

                rsum -= routsum;
                gsum -= goutsum;
                bsum -= boutsum;
                stackstart = stackpointer - radius + div;
                sir = stack[stackstart % div];

                routsum -= sir[0];
                goutsum -= sir[1];
                boutsum -= sir[2];

                if (x == 0) {
                    vmin[y] = Math.min(y + r1, hm) * w;
                }
                p = x + vmin[y];
                sir[0] = r[p];
                sir[1] = g[p];
                sir[2] = b[p];
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
                rsum += rinsum;
                gsum += ginsum;
                bsum += binsum;

                stackpointer = (stackpointer + 1) % div;
                sir = stack[stackpointer];

                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
                rinsum -= sir[0];
                ginsum -= sir[1];
                binsum -= sir[2];

                yi += w;
            }
        }
        return pix;
    }
}
